Adjustable boom attachment

ABSTRACT

An adjustable boom for use as an attachment to a fork lift truck. The boom includes an upper horizontal boom element which is slidably received in a carrier on the vertical upright means of the attachment so as to be selectively disposable in a forwardly extended lifting disposition and a rearward retracted disposition. Means are provided for varying the extent of the boom forwardly of the upright and an extension element is provided on the boom for further extending the forward projection of the support means. The upright includes adjustable means for varying the elevation of the horizontal boom element above the ground. Means are provided for locking the upright in a preselected position to cause the boom element to extend in a preselected fore and aft direction. Alternatively, the locking means may be arranged to permit swinging of the boom about the vertical axis. An upright may be provided on each of a pair of fork lift trucks for carrying the opposite ends of a bridging boom arranged to carry a load from the mid-portion thereof.

United States Patent 11 1 Dilny 1 I ADJUSTABLE BOOM ATTACHMENT [76] Inventor: Mike M. Dilny, 4855 North Western Ave., Chicago, 111. 60625 22 Filed: June 13, 1972 21 Appl. No.: 262,358

[52] US. Cl. 214/620, 212/46 B, 212/64 [51] Int. Cl 866i 9/06 [58] Field of Search 214/620, 621, 653, 654, 214/75 R; 212/46 B, 64; 254/1391 [56] References Cited UNITED STATES PATENTS 2,194,125 3/1940 Rinehart 212/64 X 2,517,085 8/1950 Cirillo 212/64 2,593,820 4/1952 Weiss 214/654 2,603,522 7/1952 Stair 214/620 3,090,494 5/1963 Thiele 214/620 X FOREIGN PATENTS OR APPLICATIONS 257,466 10/1967 Austria 214/621 166,307 2/1959 Sweden 212/46 B OTHER PUBLICATIONS Lift Truck Attachments, from Mechanical Handling Magazine, May, 1967 issue, pages 200 & 201.

[ 1 Dec.3,1974

Primary Examiner-Robert J. Spar Attorney, Agent, or Firm-Wegner, Stellman, McCord, Wiles & Wood 5 7 ABSTRACT An adjustable boom for use as an attachment to a fork lift truck. The boom includes an upper horizontal boom element which is slidably received in a carrier on the vertical upright means of the attachment so as to be selectively disposable in a forwardly extended lifting disposition and a rearward retracted disposition. Means are provided for varying the extent of the boom forwardly of the upright and an extension element is provided on the boom for further extending the forward projection of the support means. The upright includes adjustable means for varying the elevation of the horizontal boom element above the ground. Means are provided for locking the upright in a preselected position to cause the boom element to extend in a preselected fore and aft direction. Alternatively, the locking means may be arranged to permit swinging of the boom about the vertical axis.

An upright may be provided on each of a pair of fork lift trucks for carrying the opposite ends of a bridging boom arranged to carry a load from the mid-portion thereof.

19 Claims, 8 Drawing Figures 1 ADJUSTABLE BOOM ATTACHMENT BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to hoisting apparatus and in particular to an adjustable boom attachment for a fork lift truck.

2. Description of the Prior Art A number of devices have been developed for providing a boom means in association with a fork lift truck. Examples of such devices are illustrated in the following US. Pat. Nos.:

Ulm Detachable Boom for In one prior art structure, the boom is attached to the forks of the truck by means of a pair of channels adapted to receive the forks.

SUMMARY OF THE INVENTION The present invention comprehends an improved adjustable boom attachment for use with a fork lift truck which permits facilitated installation and removal from the fork lift truck as desired while yet providing a sturdy, easily adjusted boom structure for hoisting loads by means of the mechanism for vertically moving the truck forks. The boom attachment includes an upright portion having a lower end removably secured to the fork lift mechanism at the front of the truck and includes means for adjustably varying the vertical extension thereof so as to dispose a horizontal boom element mounted in a carrier at the top of the upright at any one of a plurality of different heights. The extension of the upright may be locked to maintain the boom element accurately in a fore and aft direction at the desired height or may be arranged to permit swinging of the boom element about the vertical axis of the upright support so as to hoist loads displaced laterally from the front of the truck.

The carrier defines a slide support permitting the boom element to be longitudinally adjustably supported therein. Thus, the boom may project forwardly from the upright in a hoisting position or may be retracted rearwardly through the carrier to a storage, or retracted position as desired. Means are provided for locking the boom in the adjusted longitudinal position and the locking means further defines means for preventing rotation of the boom in the carrier.

The boom may include an extension element slidably carried therein to project forwardly from the front end of the main boom element for hoisting loads spaced further forwardly from the truck than may be handled by the main boom element.

In a modified form of the invention, the boom element may comprise a bridging means extending between two attachments carried respectively on a pair of fork lift trucks to permit the hoisting of a load from the mid-portion of the boom between the two trucks. In

this modified form of the invention, the boom may comprise an I-beam adjustably positioned on the pair of uprights by a modified carrier suitably adapted to engage the flanges of the beam in the assembled relationship. Thus, in the illustrated embodiments, the booms include a longitudinal web portion and the carriers include means cooperating with the web for securing the boom against rotation about the longitudinal axis thereof. Thus, the adjustable boom attachments of the present invention are extremely simple and economical of construction while yet providing the highly desirable features discussed above.

BRIEF DESCRIPTION OF THE DRAWING Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

FIG. 1 is a side elevation of an adjustable boom attachment embodying the invention mounted on the front portion of a conventional fork lift truck;

FIG. 2 is a fragmentary side elevation illustrating the arrangement of the upright support to permit swinging of the boom element about the vertical axis of the upright support;

FIG. 3 is a front elevation thereof;

FIG. 4 is a top plan view thereof with the boom element being shown in different angular positions in broken lines;

FIG. 5 is a vertical section taken substantially along the line 5-5 of FIG. 1;

FIG. 6 is a plan view of a modified form of adjustable boom attachment embodying the invention mounted on the front of a pair of fork lift trucks;

FIG. 7 is a fragmentary side elevation thereof; and

FIG. 8 is a fragmentary front elevation thereof with a portion broken away to facilitate illustration of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the exemplary embodiment of the invention as shown in FIGS. 1-5 of the drawing, a boom attachment generally designated 10 is shown to comprise an upright support portion generally designated 11 adapted to be removably secured to the front end of a conventional fork lift truck generally designated 12. The upright support 11 includes a carrier 13 on an upper extension portion 14 thereof which horizontally adjustably carries a boom element 15. The fork lift truck 12 includes suitable conventional mechanism generally designated 16 for selectively raising and lowering a mounting portion 17 to which the lower base portion 18 of the upright support 11 is secured. Thus, in use, the boom element 15 may be provided with a suitable hoisting hook 19 for hoisting a load forwardly of the truck 12 by suitable operation of the fork lift mechanism. The boom element 15 may be retracted longitudinally through carrier 13 to overlie the truck 12 when it is desired to utilize the fork lift truck in the normal manner with the normal fork elements (not shown) attached to the mechanism 17, without the necessity of removing the attachment 10 from the truck 12. Thus, the present invention provides a substantial improved facility in the use of the fork lift truck selectively in the normal manner or as a hoisting device.

More specifically, the base 18 of the upright support 11 includes a lower tubular section 20 secured to the mechanism 17 by a U-shaped retainer 21. The upper portion 22 of the base 18 is provided with two pairs of diametrically aligned openings 23 adjacent a top edge 24 thereof for selectively receiving a pin 25. The cylindrical upper portion 14 of the upright is provided with spaced through bores 26 permitting the pin to pass through the selected openings 23 and a selected v through bore 26 to lock the upper extension portion 14 in any one of a plurality of different elevations thereby to adjust the height of the boom element as desired. The extension of the pin 25 through the holes 23 and selected bore 26 locks the extension portion 14 against rotation about the vertical axis of the upright support 11 to maintain the boom element accurately parallel to the fore and aft direction of the fork lift truck. The pin 25 may be retained on the base portion 22 by a suitable chain 27 to prevent loss of the pin.

When it is desired to adjust the angular position of the boom element 15 about the vertical axis of the upright support as illustrated in FIG. 4 of the drawing, the pin 25 may be disposed in the selected through bore 26 above the top edge 24 of the base support portion 22.

' Thus, the pin may roll along the top edge 24 to permit the selected angular positioning while maintaining the boom element 15 at the selected height. Two such angularly displaced positions of the boom element 15 are illustrated in broken lines in FIG. 4 with relationship to the fore and aft preselected position of the boom element effected by the use of openings 23 in connection with pin 25, as shown in full lines in FIG. 4.

Carrier 13 may be secured to the upper end of the upright extension portion 14 suitably as by weldingrAs shown in FIG. 5, the carrier defines a generally cylindrical through bore 13a and a longitudinal slot 13b extending downwardly from the cylindrical bore 130. The slot 13b extends forwardly through forward, laterally spaced extensions 28 of the carrier which are provided with aligned openings 29 for receiving a pin 30 retained to the extensions 28 by a suitable chain 31. The boom element 15 includes an upper tubular portion 32 and a lower depending longitudinally extending web 33. Web 33 is provided with a plurality of longitudinally spaced through openings 34 adapted to permit the passage of the pin 30 therethrough to retain the boom element 15 in any one of a number of different extensions forwardly from the carrier 13 thereby to space the support hook l9 correspondingly in preselected different dispositions forwardly of the truck 12. Tubular portion 32 is slidably received in the cylindrical bore 13a of the carrier 13 and the web 33 is slidably received in the slot 13b of carrier 13 to lock the boom element against rotation about the horizontal axis of tubular portion 32 while yet providing facilitated longitudinal adjustment of the boom element in the carrier.

When the boom attachment is not being utilized, the boom element 15 may be retracted to a storage position, wherein it extends primarily over the truck 12 rearwardly of the carrier 13, by sliding the boom element rearwardly through the carrier to align the forwardmost openings 34 with the openings 29 and permitting locking of the boom element in the rearward retracted position by inserting the pin 30 through the aligned openings 29 and 34.

The boom element 15 may be provided with an extension element 35 comprising a cylindrical member slidably fitted in the tubular portion 32 of the boom element 15 to project forwardly therefrom. The extention element may be provided at its forward end with a suitable hook 36 for supporting a load to be hoisted at a point forwardly of the forward end of the boom element 15. As illustrated in FIG. 1, the extension element 35 may have a length the major portion of the length of boom element portion 32 so as to provide a substantial forward extension of the hoist means when desired.

The extension 35 may be provided with a plurality of longitudinally spaced through bores 43 and a bolt 44 may be extended through the tubular portion 32 of the boom element 15 and a selected one of the bores 43 to lock the extension element 35 in a desired position. As shown in FIG. 1, the bolt 44 may be extended through the forwardmost hole 43a to secure the extension element in a fully retracted position within the tubular element 32 for self-storing of the extension element when not in use.

Referring now to the embodiment of FIGS. 6-8, a modified form of hoisting means generally designated embodying the invention is shown to comprise a pair of upright supports 111 adapted to be secured to the front end of a pair of fork lift trucks 12. The boom element of attachment 110 comprises a bridging element 115 which extends between the carriers 113 of the two upright supports to support a load such as load L illustrated in FIG. 6, from a mid-portion 137 of the boom element between the two trucks 12.

As shown in FIGS. 7 and 8, the upright supports 111 include lower base portions 118 similar to the base portion 18 of upright support 11. The boom 115, as shown, may comprise an I-beam having its lower flanges 138 secured to the carrier 113 which includes top plate 139 of an insert post 140 received in the upper end of the tubular base 118, as shown in FIG. 8. The flanges 138 are secured to the plate 139 by suitable elbow screws 141 and cooperating nuts 142. The insert 140 is free to rotate in the tubular support 118 permitting the boom 1 15 to be angularly adjusted relative to the vertical axis of the two supports 111 as shown in FIG. 6. Thus, the adjustable hoist means 110 may utilize the same base portion of the uprights 11 of adjustable boom 10 with the carrier 113 replacing the upper portion 14 of the support 11 and carrier 13, and with the I-beam 115 replacing the boom element 15. Use of the hoisting means 110 may be desired where relatively heavy loads are to be hoisted which might tend to overload the boom structure 10 tending to tip the fork lift truck. While the arrangement of the trucks 12 in FIG. 6 is a laterally spaced side-by-side arrangement, as will be obvious to those skilled in the art, the trucks may be arranged in other arrangements such as spaced face-toface association, spaced front to rear arrangement, etc.

The adjustable boom attachments of the present invention are extremely simple and economical of construction while yet providing facilitated adjustable disposition thereof both in locating the hoisting hook forwardly of the truck and in arranging the structure in a retracted disposition for normal use of the fork lifting means of the truck as desired. The use of the bridging means 115 may be effected quickly and easily by simple substitution of the boom 115 and carriers 113 for the upright portion 14, carrier 13 and boom element 15 of the attachment l0.

The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the invention.

I claim:

1. For use with a fork lift truck having a vertically movable lift member, an adjustable boom attachment comprising: an upright support; means for securing the support to the lift member for vertical movement therewith; a carrier mounted on said support and defining a through horizontal passage; a boom longitudinally movably fitted in said carrier passage and having a forward end selectively spaced forwardly of said upright support for supporting a load therefrom and disposed adjacent said support in a rearward, retracted position with the majority of the boom extending horizontally rearwardly of the upright support permitting the fork lift truck to be used in a normal manner without removal of the adjustable boom attachment therefrom.

2. The fork lift truck adjustable boom attachment of claim 1 wherein said carrier passage defines a noncircular cross section and said boom defines a similar noncircular cross section for longitudinally movable, nonrotative mounting of the boom therein.

3. The fork lift truck adjustable boom attachment of claim 1 wherein said boom includes a longitudinal web, and said carrier includes means cooperating with said web for preventing rotation of the boom about the longitudinal axis thereof.

4. The fork lift truck adjustable boom attachment of claim 1 wherein said support includes a lower base member to be secured to the lift member, and an upper extension member projecting vertically adjustably upwardly from said base member, and means for retaining said extension member in any one of a plurality of adjusted positions to adjust correspondingly the height of the boom relative to the fork lift member.

5. The fork lift truck adjustable boom attachment of claim 1 including means for releasably locking the boom in any one of a plurality of different longitudinally adjusted positions relative to said carrier.

6. The fork lift truck adjustable boom attachment of claim 1 wherein said support includes a lower base member to be secured to the lift member, and an upper extension member projecting vertically adjustably upwardly from said base member, and means for retaining said extension member in any one of a plurality of adjusted positions to adjust correspondingly the height of the boom relative to the fork lift member, said retaining means being arranged to permit swinging of the extension member about a vertical axis for correspondingly swinging said boom.

7. The fork lift truck adjustable boom attachment of claim 1 wherein said support includes a lower base member to be secured to the lift member, and an upper extension member projecting vertically adjustably upwardly from said base member, and means for retaining said extension member in any one of a plurality of adjusted positions to adjust correspondingly the height of the boom relative to the fork lift member, said base member comprising a socket member and said extension member comprising a male member rotatable in said socket member about a vertical axis, said retaining means comprising pin means and radial holes in said socket member and male member, said pin means being selectively received in aligned holes of said socket member and male member for retaining the male member nonrotatively in a selected position on the socket member or received in a hole of the male member and overlying the socket member for retaining the male member rotatively about said vertical axis in a selected vertical position on the socket member.

8. The fork lift truck adjustable boom attachment of claim 1 including means for selectively locking the carrier against rotation about a vertical axis with the boom extending directly forwardly from the fork lift truck, or permitting swinging of the carrier about a vertical axis on the support for angularly adjustably positioning the boom.

9. The fork lift truck adjustable boom attachment of claim 1 wherein said boom is provided with an extension element adjustably carried by the boom to extend forwardly from said forward end for supporting a load forwardly of said boom forward end. I

it). The fork lift truck adjustable boom attachment of claim 1 wherein said boom includes means defining a plurality of longitudinally spaced holes and load connecting means selectively received in said holes, and means are further provided on said carrier for selective reception in said holes to lock said boom to said carrier in any one of a plurality of preselected longitudinally spaced positions.

11. The fork lift truck adjustable boom attachment of claim ll wherein said support includes a base member defining an upwardly opening socket, and means removably received in said socket for removably carrying said carrier and boom.

12. For use with a fork lift truck having a vertically movable lift member, an adjustable boom attachment comprising: an upright support defining an upwardly opening socket; means for securing the support to the lift member for vertical movement therewith; a carrier including a male portion removably fitted in said socket whereby said carrier is mounted on said support, said carrier defining a through horizontal passage; a boom longitudinally movably fitted in said carrier passage and having a forward end selectively spaced forwardly of said upright support for supporting a load therefrom and disposed adjacent said support in a rearward, retracted position with the majority of the boom extending horizontally rearwardly of the upright support permitting the fork lift truck to be used in a normal manner without removal of the adjustable boom attachment therefrom.

13. The fork lift truck lift boom attachment of claim 12 wherein said boom comprises an I-beam.

14. The fork lift truck lift boom attachment of claim 112 wherein said socket is circular in cross section and said male portion is complementary thereto to permit swinging of the boom about the vertical axis of the socket.

15. The fork lift truck lift boom attachment of claim 12 wherein said socket is circular in cross section and said male portion is complementary thereto to permit swinging of the boom about the vertical axis of the socket, and means are provided for selectively locking the male portion against rotation about said axis.

16. The fork lift truck lift boom attachment of claim 12 wherein said socket is circular in cross section and said male portion is complementary thereto to permit swinging of the boom about the vertical axis of the socket, and means are provided for selectively locking the male portion against rotation about said axis comprising registering holes in said support and male portion and a pin selectively receivable therein.

17. The fork lift truck lift boom attachment of claim 12 including a second such carrier for mounting the boom remotely from said first named mounting means to a second such support, and means for securing said second support to the lift member of a second such fork lift truck whereby the boom may be supported at spaced positions on a pair of spaced fork lift trucks for supporting a load therebetween.

18. The fork lift truck lift boom attachment of claim the clamp means to the boom. 

1. For use with a fork lift truck having a vertically movable lift member, an adjustable boom attachment comprising: an upright support; means for securing the support to the lift member for vertical movement therewith; a carrier mounted on said support and defining a through horizontal passage; a boom longitudinally movably fitted in said carrier passage and having a forward end selectively spaced forwardly of said upright support for supporting a load therefrom and disposed adjacent said support in a rearward, retracted position with the majority of the boom extending horizontally rearwardly of the upright support permitting the fork lift truck to be used in a normal manner without removal of the adjustable boom attachment therefrom.
 2. The fork lift truck adjustable boom attachment of claim 1 wherein said carrier passage defines a noncircular cRoss section and said boom defines a similar noncircular cross section for longitudinally movable, nonrotative mounting of the boom therein.
 3. The fork lift truck adjustable boom attachment of claim 1 wherein said boom includes a longitudinal web, and said carrier includes means cooperating with said web for preventing rotation of the boom about the longitudinal axis thereof.
 4. The fork lift truck adjustable boom attachment of claim 1 wherein said support includes a lower base member to be secured to the lift member, and an upper extension member projecting vertically adjustably upwardly from said base member, and means for retaining said extension member in any one of a plurality of adjusted positions to adjust correspondingly the height of the boom relative to the fork lift member.
 5. The fork lift truck adjustable boom attachment of claim 1 including means for releasably locking the boom in any one of a plurality of different longitudinally adjusted positions relative to said carrier.
 6. The fork lift truck adjustable boom attachment of claim 1 wherein said support includes a lower base member to be secured to the lift member, and an upper extension member projecting vertically adjustably upwardly from said base member, and means for retaining said extension member in any one of a plurality of adjusted positions to adjust correspondingly the height of the boom relative to the fork lift member, said retaining means being arranged to permit swinging of the extension member about a vertical axis for correspondingly swinging said boom.
 7. The fork lift truck adjustable boom attachment of claim 1 wherein said support includes a lower base member to be secured to the lift member, and an upper extension member projecting vertically adjustably upwardly from said base member, and means for retaining said extension member in any one of a plurality of adjusted positions to adjust correspondingly the height of the boom relative to the fork lift member, said base member comprising a socket member and said extension member comprising a male member rotatable in said socket member about a vertical axis, said retaining means comprising pin means and radial holes in said socket member and male member, said pin means being selectively received in aligned holes of said socket member and male member for retaining the male member nonrotatively in a selected position on the socket member or received in a hole of the male member and overlying the socket member for retaining the male member rotatively about said vertical axis in a selected vertical position on the socket member.
 8. The fork lift truck adjustable boom attachment of claim 1 including means for selectively locking the carrier against rotation about a vertical axis with the boom extending directly forwardly from the fork lift truck, or permitting swinging of the carrier about a vertical axis on the support for angularly adjustably positioning the boom.
 9. The fork lift truck adjustable boom attachment of claim 1 wherein said boom is provided with an extension element adjustably carried by the boom to extend forwardly from said forward end for supporting a load forwardly of said boom forward end.
 10. The fork lift truck adjustable boom attachment of claim 1 wherein said boom includes means defining a plurality of longitudinally spaced holes and load connecting means selectively received in said holes, and means are further provided on said carrier for selective reception in said holes to lock said boom to said carrier in any one of a plurality of preselected longitudinally spaced positions.
 11. The fork lift truck adjustable boom attachment of claim 1 wherein said support includes a base member defining an upwardly opening socket, and means removably received in said socket for removably carrying said carrier and boom.
 12. For use with a fork lift truck having a vertically movable lift member, an adjustable boom attachment comprising: an upright support defining an upwardly opening socket; means For securing the support to the lift member for vertical movement therewith; a carrier including a male portion removably fitted in said socket whereby said carrier is mounted on said support, said carrier defining a through horizontal passage; a boom longitudinally movably fitted in said carrier passage and having a forward end selectively spaced forwardly of said upright support for supporting a load therefrom and disposed adjacent said support in a rearward, retracted position with the majority of the boom extending horizontally rearwardly of the upright support permitting the fork lift truck to be used in a normal manner without removal of the adjustable boom attachment therefrom.
 13. The fork lift truck lift boom attachment of claim 12 wherein said boom comprises an I-beam.
 14. The fork lift truck lift boom attachment of claim 12 wherein said socket is circular in cross section and said male portion is complementary thereto to permit swinging of the boom about the vertical axis of the socket.
 15. The fork lift truck lift boom attachment of claim 12 wherein said socket is circular in cross section and said male portion is complementary thereto to permit swinging of the boom about the vertical axis of the socket, and means are provided for selectively locking the male portion against rotation about said axis.
 16. The fork lift truck lift boom attachment of claim 12 wherein said socket is circular in cross section and said male portion is complementary thereto to permit swinging of the boom about the vertical axis of the socket, and means are provided for selectively locking the male portion against rotation about said axis comprising registering holes in said support and male portion and a pin selectively receivable therein.
 17. The fork lift truck lift boom attachment of claim 12 including a second such carrier for mounting the boom remotely from said first named mounting means to a second such support, and means for securing said second support to the lift member of a second such fork lift truck whereby the boom may be supported at spaced positions on a pair of spaced fork lift trucks for supporting a load therebetween.
 18. The fork lift truck lift boom attachment of claim 17 wherein each said socket is circular in cross section and each said male portion is complementary thereto to permit swinging of the boom about the vertical axis of the socket.
 19. The fork lift truck lift boom attachment of claim 17 wherein each said carrier comprises clamp means and threaded securing means for adjustably securing the clamp means to the boom. 